This grant has supported work dealing exclusively with the design and development of new histochemical methods for enzymes and functional groups of macromolecules for both the light and electron microscope. With the recent development of a specific method for prostatic acid phosphatase (PAP) we will continue to study the distribution and localization of PAP in normal prostatic epithelium and prostatic adenocarcinoma with the light and electron microscope, and its possible use as a specific diagnostic tool. The program dealing with drug design and development for prostatic carcinoma is supported (since March, 1974) by research grant CA16077 from the National Prostatic Cancer Project, NCI. Our histochemical studies help the drug development project with structural and activity relationships of new drugs for prostatic carcinoma. Also, tissue from treated primates will be studied cytochemically and morphologically by this grant.